A Syrian city divided by a wall, Vietnamese villagers fight back against land grabs, and more

This show is made up entirely of amateur images. We've seen time and time again how images captured by ordinary citizens then uploaded onto the Web can change history, or at least shift the balance of power. This week, we take a look back at some of those moments.

STORY 1: Syria

We begin today once again in the Syrian city of Homs, specifically its Baba Amr neighborhood. Homs is known as being one of the toughest centers of protest against the regime of Bashar al Assad. And within Homs, Baba Amr has been the heart of the opposition. The neighborhood has been largely destroyed by Syrian artillery, and most of its inhabitants have fled. Now the Syrian forces have walled it off - literally. They've built a concrete wall two kilometers long to separate it from the rest of the city. Our Observer, activist Saleem Kabbani, lives in Homs, and got close enough to see the wall himself.

STORY 2: Vietnam

Now to Vietnam, to the countryside outside the capital Hanoi. The government wants to turn 70 hectares of farmland into a brand new satellite city called Ecopark. Local farmers are calling it a land grab. Like in China, all land in Vietnam is state property, but usage and residency rights are often unclear. When the farmers heard the state planned to take the land by force, they camped out to defend it. Then on April 24, riot police moved in. Our Observer Nu-when Thanh Giang has the story - which has not been covered by the state media.

STORY 3: World

Now for our weekly roundup of the best images and stories sent in by our Observers.

First stop, China, and its universities. Our Observer Cheng tells us that competition to get into the right postgraduate program is intense. When it gets close to exam time, classrooms fill up and tempers fray. At Shandong University in the east, students have chained up their desks so they don't lose them. There have even been fistfights over who sits where. For Cheng, this is obviously going too far, but she says it reflects the students' broader fears about finding work in the ultracompetitive job market.

We end today with an impressive tornado - here in France. It happened near the southern city of Toulouse. It only lasted for a few minutes, just enough for people to get out their cellphones to film it. Tornadoes are rare in France - a twister in the north killed several people four years ago. This time, happily, no injuries were reported.